Device and method for forming packaging units

ABSTRACT

An apparatus for shrinking films to form a product bundle includes a shrink tunnel, and a conveyor that conveys product bundles through the shrink tunnel. The conveyor includes a linear transporter having a forward run and a return run along which said individually controllable displacement elements circulate.

RELATED APPLICATIONS

This application is the national stage under 35 USC 371 of international application PCT/EP2014/061657, filed on Jun. 5, 2014, which claims the benefit of the Jun. 7, 2013 priority date of German application DE 102013105923.6, the contents of which are herein incorporated by reference.

FIELD OF INVENTION

The invention relates to a packaging, and in particular, to shrink-wrapping.

BACKGROUND

It is often useful to bundle several articles together to form a product bundle and to shrink-wrap the bundle.

To form a container bundle, upright containers are transported along a bulk conveyor. The containers eventually encounter a lane divider that divides them into single track conveyor streams. The number of such streams depends on the number of columns in the bundle. The containers are then separated into clusters based on how many rows are to be in the completed bundle.

After a cluster if formed, it is shrink-wrapped. This involves wrapping the cluster in shrink-film and passing it through a shrink-tunnel where it is exposed to heat. The heat shrinks the shrink-film tightly over the package.

A known conveyor element for conveying such bundles through a shrink-tunnel is a circulating chain conveyor in which a carrier is configured as a flat-top chain. The carrier moves along a forward run and a return run to form an endless conveyor. A carrier spends half of its time in the forward run and the other half of its time on the return run. In the forward run, the carrier supports a container. In the return run, the carrier is not supporting anything.

The temperature inside the shrink-tunnel has a value that at least equals the shrink temperature of the film section concerned. However, the value must not be so high as to harm the product present in the containers.

Closure elements are provided at both the entry and exit sides. Examples of closure elements include louver curtains or gates. These prevent temperature losses during both normal operation and in case of breakdowns. The shrink-tunnel is also sealed above and below.

The shrinking process inside the shrink-tunnel is carried out by way of temperature-controlled air flows in shrink-tunnel zones. The temperatures prevailing inside the shrink-tunnel must at all times ensure that the shrink-film is evenly shrunk. Many shrink-tunnels are divided into a plurality of heating or tunnel zones, possibly each with its own heating means. This also applies to the support-surface of the bundle on the carrier region concerned.

SUMMARY

It is an object of the invention to provide a device that reduces energy losses and eliminates uneven appearance of shrink-film.

In one aspect, the invention features a device for shrinking films and/or film sections around products or groups of products, particularly bundles. Such a device includes a shrink-tunnel, at least one conveyor element on which the bundles can be conveyed in an upright position from an entry end to an exit side of the shrink-tunnel. The conveyor element comprises a linear transporter on which individually controllable displacement elements circulate along a forward and return run thereof. These have either tray-like or panel-like carriers.

In some embodiments, the size of the carrier corresponds to a support-surface of the bundle. In other embodiments, the carrier, or the displacement element, comprises one or more adjusters to individually adjust the carrier's size to correspond to a bundle's support-surface. Among these embodiments are those in which the adjusters adjust telescopically. These permit continuous adjustability between a neutral position, a maximum position, and a minimum position. As a result, the standing bundle completely, or at least almost completely, covers the carrier. This promotes energy conservation because only the area of the carrier in question, and perhaps a small edge projecting around the bundle, will require heating.

In another embodiment, the displacement element is individually connectable to a separate carrier by gripping. This is achieved by providing grippers. The grippers, which are arranged on the displacement element, grip the separate carrier in a transfer station, and move it to the bundle that is to be transported. After the cycle, the gripper releases the carriers so that they can be deposited again in the transfer station. In some embodiments, the grippers are arranged on the displacement element so as to move transversely and/or longitudinally. In other embodiments, the grippers also perform the function of adjusters. The separate carrier can, of course, also be gripped once its size has been adapted

In some embodiments, the displacement elements are controlled in such a way that at least two carriers combine to form a transport group that is preferably adapted to the support-surface. More than two carriers can also be combined in this way.

In some embodiments, the linear transporter is an electromagnetic direct drive on whose conveyor path the displacement elements circulate as movers or skids.

Among these are embodiments in which the linear transporter comprises a continuous conveyor path on which individual displacement elements circulate. These displacement elements are individually controllable such that each displacement element can have its own speed. On a forward run of their trajectory, the displacement elements all travel at the same speed. On the return run, the displacement elements can have a different speed. This means that displacement elements moving along the return run can move faster than displacement elements moving along the forward run. As a result, only a very small number of displacement elements will be needed.

In some embodiments, the path along which displacement elements move has a gate to allow the removal of displacement elements that are either not needed or that are malfunctioning in some way. Such a gate also permits introducing additional displacement elements.

Other embodiments include a waiting station for the displacement elements. At the waiting station the displacement elements, and in particular, the carriers arranged thereon, are brought into overlapping position.

In other embodiments, the conveyor path comprises a conveyor path section to the transfer station and away from it if separate carriers are to be gripped.

Other embodiments feature heat shields to shield displacement elements from excessive heat while inside the shrink-tunnel. Embodiments include both those with travelling shields and those with permanently-installed shields. In either case the shields are configured to avoid hampering the shrink-tunnel's ability to evenly shrink the film onto the bundle.

In some embodiments, the linear transporter includes an electromagnetic track on which directly-controllable displacement elements circulate gearlessly. As a result, it is possible to select a desired speed for any particular displacement element. Embodiments include those that have an interface between the linear transporter and a controller to permit such control.

Embodiments include those in which the displacement element drags the carrier.

In other embodiments, the carrier is a chain mail-like carrier adapted to the size of the bundle's support-surface.

In yet other embodiments, the individual controllability of displacement elements permits two or more carriers to combine to form a transport group that is adapted to the bundle's support-surface. The two or more carriers combine either in an overlapping manner or in a non-overlapping manner.

The presence of individually controllable displacement elements permits bundles to be conveyed through the shrink-tunnel continuously, i.e. at an appropriately adapted speed. Along the return run, the displacement elements can be moved at a correspondingly greater speed than along the forward run. As a result, one need only provide a very small number of displacement elements, most of which will be along the forward run while the few remaining are moving rapidly back along the return run.

In some embodiments, the shrink-tunnel is part of a packaging machine that forms bundles from a wide container stream. Among these are embodiments in which the shrink-tunnel is a final station of the packaging machine.

In one aspect, the invention features an apparatus for shrinking films to form a product bundle. Such an apparatus includes a shrink-tunnel having an entry and an exit, and a conveyor that conveys upright bundles through the shrink-tunnel therebetween. The conveyor features a linear transporter having a forward run and a return run along which individually controllable displacement elements circulate. Each of the displacement elements includes a carrier.

In some embodiments, the carrier's size is adapted to a support-surface of the product bundle.

In other embodiments, the carrier includes an adjuster for adjusting a size of the carrier to adapt to a support-surface of the product bundle. Among these are embodiments in which the adjusters are telescopically configurable.

Other embodiments include those in which each of the displacement elements includes a gripper that is movable for gripping a carrier.

In yet other embodiments, the displacement elements are configured to transition between a first state, in which carriers combine to form a transport group that is adapted to support a support-surface of a bundle, and a second state, in which the carriers have separated so as to no longer form the transport group.

Some embodiments also include support elements that support the carriers along the forward run.

In some embodiments, the linear transporter includes an electromagnetic direct drive. Among these are embodiments in which the linear transporter includes skids and/or movers on which the displacement elements circulate.

In some embodiments, the conveyor includes a waiting station for the displacement elements.

In other embodiments, carriers transition between a first state, in which they overlap, and a second state, in which they do not.

Yet other embodiments include shields that travel with the displacement elements along at least certain regions.

In some embodiments, the apparatus also has a packaging machine upstream of the shrink-tunnel. This packaging machine supplies product bundles to the shrink-tunnel.

Yet other embodiments include those in which each carrier includes a tray, and those in which each carrier includes a panel.

In another aspect, the invention features a method for producing product bundles. Such a method includes providing a product bundle on a conveyor that includes a linear transporter, supporting an upright bundle with individually controllable displacement elements that circulate on the conveyor, each of which has a carrier that participates in support of the bundle, and conveying the bundle through a shrink-tunnel.

Some practices of the method also include controlling the displacement elements so as to combine at least two carriers that together support the bundle during conveyance thereof through the shrink-tunnel.

Other practices include causing the displacement elements to continuously move the bundle through the shrink-tunnel.

Yet other practices include causing the displacement elements to move more slowly on forward run of the conveyor than they do on a return run of the conveyor.

Also among the practices of the invention are those that further include causing there to be more displacement elements on a forward run of the conveyor than there are on a return run of the conveyor.

In another aspect, the invention features an apparatus for shrinking films to form a product bundle. Such an apparatus includes a shrink-tunnel and a conveyor that conveys product bundles through the shrink-tunnel. The conveyor includes a linear transporter having a forward run and a return run along which the individually controllable displacement elements circulate.

As used herein, “containers” refers to bottles, cans, tubes, and pouches, whether from metal, glass and/or plastic, and include PET bottles and other packaging elements, in particular those that are suitable for the filling of liquid or viscous products or also for holding foods, as well as containers already combined into groups, such as in a multipack or a bundle.

Further embodiments, advantages and possible applications of the invention arise out of the following description of embodiments. All of the described attributes whether alone or in any desired combination are fundamentally the subject matter of the invention independently of their synopsis in the claims or a retroactive application thereof. The content of the claims is also made an integral part of the description.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the invention will be apparent from the following detailed description and the accompanying drawings, in which:

FIG. 1 shows a schematic view of a shrink-tunnel of a packaging machine; and

FIG. 2 shows the shrink-tunnel of FIG. 1 with an extended conveyor path

DETAILED DESCRIPTION

FIG. 1 shows a shrink-tunnel 1 for the shrinking of films and/or film sections around products or product groups, particularly around bundles 2. A conveyor element 3 passes through the shrink-tunnel 1. The conveyor element 3 conveys upright bundles 2 from an entry 4 to an exit 5 of the shrink-tunnel 1.

The conveyor element 3 includes a linear transporter 8 on which individually controllable displacement elements 9 circulate. The displacement elements 9, each of which includes a tray-like or panel-like carrier 10, move along a forward run 6 of the conveyor element 3 through the shrink-tunnel 1 and return along a return run 7 to the beginning of the forward run 6.

Each carrier 10 is formed from a flexible material. An example of a suitable flexible material is chain-mail.

As can be seen from FIG. 1, a carrier 10 is too small to support a bundle 2 by itself because its surface area is considerably smaller than that of a bundle 2. Consequently, to support a bundle 2, displacement elements 9 are combined to form a transport group 11 with carriers 10, if necessary, overlapping one another. The transport group 11 is adapted to the support-surface of bundle 2.

In the embodiment shown in FIG. 1, the linear transporter 8 comprises an electromagnetic direct drive having a conveyor path on which displacement elements 9 circulate as movers or skids. The linear transporter 8 has a continuous conveyor path on which individual circulating displacement elements 9 are arranged. Each displacement element 9 is individually controllable. As a result, each displacement element 9 can move with a speed that differs from that of other displacement elements 9.

Displacement elements 9 move along a return run 7 and along a forward run 6 with different speeds. This reduces the total number of displacement elements 9 required because displacement elements 9 that have just finished conveying a bundle 2 along the forward run 6 can move very quickly along the return run 7 so that they can be made available sooner to convey another bundle 2.

FIG. 2 shows a shrink-tunnel 1 similar to that of FIG. 1 in which the linear transporter 8, together with some of its displacement elements 9, extends outside the shrink-tunnel 1. This creates a speed-adjustment region 12 outside the shrink-tunnel 1. The speed-adjustment region can be provided either before the entry 4 of the shrink-tunnel 1 or at the exit 5 from shrink-tunnel 1.

A speed-adjustment region 12 provides greater flexibility in moving bundles 2. Typically, bundles 2 are transported at constant speed inside the shrink-tunnel 1 on the forward run 6 because the heat from the shrink-wrap machine must be given time to work. However, once outside the shrink-tunnel 1, there are no such constraints on container speed. Upstream and downstream process steps are largely immaterial for the shrinking process. 

Having described the invention, and a preferred embodiment thereof, what we claim as new, and secured by Letters Patent is: 1-15. (canceled)
 16. An apparatus for shrinking films to form a product bundle, said apparatus comprising a shrink tunnel, a conveyor, and individually controllable displacement elements, wherein said conveyor conveys upright bundles from an entry of said shrink tunnel to an exit of said shrink tunnel, wherein said conveyor comprises a linear transporter having a forward run and a return run along which said individually controllable displacement elements circulate, and wherein each of said displacement elements comprises a carrier.
 17. The apparatus of claim 16, wherein said carrier has a size that is adapted to a support surface of said product bundle.
 18. The apparatus of claim 16, wherein said carrier comprises an adjustment element for adjusting a size of said carrier to adapt to a support surface of said product bundle.
 19. The apparatus of claim 16, wherein said carrier comprises adjustment elements that are telescopically configurable.
 20. The apparatus of claim 16, wherein each of said displacement elements comprises a gripper that is movable for gripping a carrier.
 21. The apparatus of claim 16, wherein said displacement elements are configured to transition between first and second states, wherein in said first state, at least two carriers combine to form a transport group that is adapted to support a support surface of a bundle, and wherein in said second state, said at least two carriers are separated so as to no longer form said transport group.
 22. The apparatus of claim 16, further comprising support elements that support said carriers along said forward run.
 23. The apparatus of claim 16, wherein said linear transporter comprises an electromagnetic direct drive.
 24. The apparatus of claim 16, wherein said linear transporter comprises skids on which said displacement elements circulate.
 25. The apparatus of claim 16, wherein said conveyor comprises a waiting station for said displacement elements.
 26. The apparatus of claim 16, wherein at least two of said carriers are configured to transition between a first state and a second state, wherein in said first state, said carriers overlap, and wherein in said second state, said carriers are separated.
 27. The apparatus of claim 16, further comprising shielding elements that travel with said displacement elements along at least certain regions.
 28. The apparatus of claim 16, further comprising a packaging machine upstream of said shrink tunnel, wherein said packaging machine supplies product bundles to said shrink tunnel.
 29. The apparatus of claim 16, wherein said carrier comprises a tray.
 30. The apparatus of claim 16, wherein said carrier comprises a panel.
 31. A method for producing product bundles, said method comprising providing a product bundle on a conveyor comprising a linear transporter, supporting an upright bundle with individually controllable displacement elements that circulate on said conveyor, each of which has a carrier that participates in support of said bundle, and conveying said bundle through a shrink tunnel.
 32. The method of claim 31, further comprising controlling said displacement elements so as to combine at least two carriers that together support said bundle during conveyance thereof through said shrink tunnel.
 33. The method of claim 31, further comprising causing said displacement elements to continuously move said bundle through said shrink tunnel.
 34. The method of any one of claims 31, further comprising causing said displacement elements to move at a first speed on a forward run of said conveyor and to move at a second speed on a return run of said conveyor, wherein said second speed is greater than said first speed.
 35. The method of claim 31, further comprising causing a first number of said displacement elements to be on a forward run of said conveyor and causing a second number of said displacement elements to be on a return run of said conveyor, wherein said first number is greater than said second number. 